% More information see ETData.m
function cut(obj, st, ed)
    l = find(obj.Time == st);
    if isempty(l)
        error('can not find start of time');
    else
        l = l(1);
    end

    u = find(obj.Time == ed);
    if isempty(u)
        error('can not find end of time');
    else
        u = u(1);
    end

    if u < l
        error('end time can not less than start time');
    end

    obj.Time = obj.Time(l:u, :);
    obj.Eddy = obj.Eddy(l:u, :);
    obj.Temp = obj.Temp(l:u, :);
    obj.m    = u - l + 1;
end
